Soft-tack, porous substrates for harvesting skin grafts

Abstract

Devices and methods for skin graft harvesting are disclosed. In one aspect of the invention, substrates for transplanting skin grafts are disclosed that include a soft-tack, biocompatible composition having a surface adapted to contact at least one excised skin graft and engage the graft for removal from a donor site. In another aspect of the invention, at least a portion of the skin-contacting surface of the substrate (or dressing) is porous to facilitate fluid transport into (or out of) the graft site during harvesting and/or transplantation. The substrates can also incorporate an absorbent component to capture fluids. The substrate can be a mesh or fabric or web, e.g. woven, knitted, nonwoven or molded. The substrate can be a mesh of biocompatible fibers, for example, cellulosic, polyolefins, polyurethanes, polyesters or polyamide fibers. In one embodiment the mesh is formed of cellulose acetate fibers and coated with a silicone gel, to imparted the desire degree of tackiness.

What is claimed is: 
     
       1. An apparatus comprising:
 a substrate formed from a fibrous material comprising an upper surface, and a lower surface configured for placement on an excised skin graft at a donor site, the upper and lower surfaces coated with a silicone composition to form a homogeneous silicone phase, and the lower surface comprising a plurality of skin graft capture sites disposed thereon, the plurality of skin graft capture sites being configured to contact the excised skin graft and capture the excised skin graft for removal from the donor site, wherein the silicone phase on the upper surface and lower surface are configured such that the upper surface comprises a tackiness of approximately 50% greater than tackiness of the lower surface; 
 a plurality of pores extending through the substrate and the silicone phase and configured to allow passage of fluids therethrough; 
 a peripheral adhesive composition disposed outwardly from a lateral border of the substrate and having an upper surface and a lower surface; 
 a first removeable backing sheet covering the lower surface of the substrate and the lower surface of the peripheral adhesive composition, and a second removable backing sheet covering the upper surface of the substrate and the upper surface of the peripheral adhesive composition; 
 a skin graft harvestor having a body portion and a detachable head portion, the body portion having an opening for placement around the skin graft capture sites, 
 wherein the substrate is positionable over the opening, and a border region of the lower surface is releasably adherable to the body portion about the opening for capturing the excised skin graft; 
 wherein the excised skin graft is adherable to the substrate by the lesser tackiness of the lower surface. 
 
     
     
       2. The apparatus of  claim 1 , wherein the silicone phase comprises an average thickness between about 500 microns (μm) and about 1000 microns (μm). 
     
     
       3. The apparatus of  claim 1 , wherein the fibrous material comprises a plurality of microfibers having an average diameter of about 0.1 to about 10 micrometers. 
     
     
       4. The apparatus of  claim 1 , wherein the fibrous material comprises a plurality of nanofibers having an average diameter of about 1 to about 100 nanometers. 
     
     
       5. The apparatus of  claim 1 , wherein the fibrous material comprises a plurality of nanofibers having an average diameter of about 20 to about 80 nanometers. 
     
     
       6. The apparatus of  claim 1 , wherein the plurality of pores comprise an average cross-section dimension ranging from about 1 nanometer to about 1 millimeter. 
     
     
       7. The apparatus of  claim 6 , wherein the plurality of pores comprise an average cross-section dimension ranging from about 1 nanometer to about 100 micrometers. 
     
     
       8. The substrate of  claim 1 , further comprising at least one port for coupling to a reduced pressure source and wherein the at least one port comprises a valve. 
     
     
       9. The substrate of  claim 8 , wherein the port further comprises a conduit configured to provide fluid communication between the absorbent material or at least one wicking layer within the chamber to an external fluid receptacle. 
     
     
       10. The apparatus of  claim 1 , wherein the substrate further comprises at least a first removable backing associated with a base layer for handling the substrate prior to positioning in the skin graft harvester and a second removable backing for handling the substrate and the skin graft prior to positioning at a recipient site. 
     
     
       11. The apparatus of  claim 1 , wherein the dressing further comprises an absorbent material. 
     
     
       12. The apparatus of  claim 11 , wherein the absorbent material comprises an open cell foamed polymer. 
     
     
       13. The apparatus of  claim 11 , wherein the absorbent material comprises a plurality of pores each having an average cross-section dimension ranging from about 0.05 millimeters to about 5 millimeters. 
     
     
       14. The apparatus of  claim 11 , wherein the absorbent material comprises a plurality of pores each having an average cross-section dimension ranging from about 0.1 millimeters to about 1 millimeters. 
     
     
       15. The apparatus of  claim 11 , wherein the absorbent material is selected from group comprising silicones, silicone gels, soft silicones, hydrocolloids, hydrogels, polyurethanes, polyurethane gels, polyolefins, polyolefin gels, hydrogenated styrenic copolymers, hydrogenated styrenic copolymer gels, foamed gels and combinations thereof. 
     
     
       16. The apparatus of  claim 1 , wherein the silicone phase comprises a degree of tackiness in a range of about 0.4N to about 2N.